Hyperactivity in animals is commonly recorded as an increase in certain coordinated movements and is caused by psychoactive drugs, such as amphetamine, an by lesions in several brain areas, notably in the front cortex and basal ganglia. Details of the behavior of rats with bilateral lesions in the frontal cortex, caudate-putamen and globus pallidus will be obtained in these experiments by placing each rat in an exploratory situation (one side of a dual chamber) and photographing it for 15 minutes. The rats will be photographed 6 weeks, 3 months and 5 months after lesioning. Lesions will be made in 5-day-old rats and in adult rats (3-4 months old). The following will be determined from the films: the duration of each of 12 motor acts, the frequency of initiation of each act and the sequencing of acts into patterns. Additional experiments will evaluate the portion of the 24-hour diurnal cycle in which hyperactivity is most pronounced by having the lesioned rats in a residential maze equipped with photocells for recording activity throughout the day. Amphetamine will be injected during the 12-hour nocturnal portions of the day to examine the effect of the stimulant to lesion-induced hyperactivity at different portions of the diurnal cycle. The animals will be photographed in the residential maze and the details of the behavior under this environmental condition will be compared with results obtained in the exploratory situtation (dual chamber). The goal of the proposed rsearch is to attempt to categorize the different kinds of hyperactivity in terms of duration, frequency and sequences of characteristic motor acts using data obtained in these and data from previous experiments.